Background. Virtual reality (VR) technology has evolved to a stage where affordable consumer devices are available. Still, there are limitations to technology which causes compromises to be made. One of the big problems in VR is locomotion, especially regarding immersion and comfort. There are two common ways for locomotion in VR, Teleportation and smooth continuous locomotion. Smooth locomotion is often considered superior for immersion but commonly causes simulation sickness.Objectives. This paper is comparing two different methods of smooth locomotion, one based on head orientation and the other based on controller orientation. The objective is to determine which method is preferred regarding comfort, immersion and ease of use.Methods. To identify the strength and weaknesses of each method, a VR experiment was designed which simulates tasks common in video games. A comparative study was made with fifteen subjects.The fifteen participants performed tasks involving exploring a VR environment and using the VR controller to shoot at targets. After using each of the methods the subjects then answered questionnaires about the usability and the simulations sickness caused by the method. Other data was collected on how well the task was performed such as number of targets hit.Results. The users ranked controller orientation locomotion higher for perceived naturalness and likeability and was ranked lower for items relating to restrictiveness and difficulty. No significant difference was found regarding simulator sickness and performance.Conclusion. Controller orientation locomotion ranked at least as good or better than head orientation locomotion in all categories. This shows that it is the preferred orientation method in this use case where the application is similar to a first person shooter game.

abstract: This thesis aims to design of wings for a laminate biped robot for providing locomotion stabilization during jump gliding. The wings are designed to collapse down during the jumping phase to maximize jump height and deployed back for gliding phase using anisotropic buckling in tape spring hinges. The project aims to develop a reliable dynamics model which can be utilized for design and evaluation of optimized systems for jump-gliding. The aerodynamic simulations are run on a vortex-lattice code which provides numeric simulations of the defined geometric bodies. The aerodynamic simulations assist in improving the design parameters such as planform, camber and twist to achieve the best possible Coefficient of Lift for maximizing glide distance. The aerodynamic simulation output is then plugged into a dynamics model built in Python, which is validated and correlated with experimental testing of a key wing designs. The experimental results are then utilized to improve the dynamics model and obtain better designs for improved performance. The simulation model informs the aerodynamic design of wings for sustaining glide for the biped platform and maximizing glide length to increase range. / Dissertation/Thesis / Masters Thesis Aerospace Engineering 2020

The mobility and biomedical applications of a microscale magnetic tumbling (μTUM) robot capable of traversing complex terrains in dry and wet environments is explored. Roughly 800 x 400 x 100 μm in size, the robot is fabricated using standard photolithography techniques and consists of a rectangular polymeric body with embedded NdFeB particles. Static force analysis and dynamic modeling of its motion characteristics are performed with experimental verification. Techniques for simulating the intermittent, non-contact behavior of tumbling locomotion are used to find an optimized design for the microrobot, reducing time and resources spent on physical fabrication. When subject to a magnetic field as low as 3 mT, the microrobot is able to translate at speeds of over 30 body lengths/s (24 mm/s) in dry conditions and up to 8 body lengths/s (6.8 mm/s) in wet conditions. It can climb inclined planes up to 60° in wet conditions and up to 45° in dry conditions. Maximum open loop straight-line trajectory errors of less than 4% and 2% of the traversal distance in the vertical and horizontal directions, respectively, were also observed. Full two-dimensional directional control of the microrobot was shown through the traversal of a P-shaped trajectory. The microrobot's real-time position can be accurately tracked through visual occlusions using ultrasound imaging. When applied as a coating, a fluorescein payload was found to diffuse over a two hour time period from the microrobot. Cytotoxicity tests also demonstrated that the microrobot's SU-8 body is biocompatible with murine fibroblasts. The microrobot's capabilities make it promising for targeted drug delivery and other in vivo biomedical applications.

L’objectif de ce travail était d’améliorer la prévention de la chute des séniors en améliorant la détection des personnes à risque et les outils d’évaluation du contrôle postural ainsi qu’en utilisant un programme de réhabilitation par électrostimulation. Afin de répondre à ces trois objectifs, trois parties ont été développées :Le but de la partie I était d’apporter des outils permettant une meilleure détection des personnes à risque à travers l’identification de facteurs responsables d’un déclin du contrôle postural. Nous avons pu établir lors de trois études que (i) les personnes consommant cinq médicaments et plus par jour présentent un risque accru des troubles de la cognition et de la mobilité, (ii) les chuteurs fracturés ont un déficit de stabilisation après le passage d’obstacle et (iii) les chuteurs fracturés réduisent moins leur vitesse de marche lors de la double tâche. Dans la partie II nous avons évalué pour la première fois le freinage du centre de masse, paramètre corrélé à la qualité du contrôle postural, avec une technique d’analyse cinématique. Il a été mis en évidence que l’analyse sur plateforme de force, habituellement utilisée, présente une plus grande variabilité et conduit à une sous-estimation de l’indice de freinage, en comparaison à cette nouvelle méthode d’analyse. Dans la partie III nous avons testé l’efficacité d’un programme d’électrostimulation des muscles mobilisateurs de la cheville sur les facteurs de risque de chute. Cet entrainement a permis d’augmenter la force des muscles et bien que la réhabilitation d’autres muscles semble nécessaire afin d’améliorer la marche, le programme a réhabilité efficacement les performances d'équilibre / The objective of this work was to improve the prevention of falls in seniors by (i) improving the detection of people at risk, (ii) providing new tools for assessing postural control and (iii) studying the effects of rehabilitation program by electrostimulation on the markers of the risk of falling. In order to meet these three objectives, three parts were developed:The aim of Part I was to provide tools for better detection of persons at risk of falls or fractures through the identification of factors responsible for a decline in postural control. We have been able to establish through three studies that (i) elderly patients who take five or more drugs per day are at higher risk of cognitive and mobility impairments, (ii) subjects who undergo fractures have a stabilization deficit after obstacle crossing and (iii) fractured fallers reduce their walking speed less during dual-task walking.In Part II we evaluated for the first time the braking of the center of mass, a parameter correlated with the quality of the postural control, with a kinematic analysis technique. It has been demonstrated that the technic usually used, the force-plate analysis, presents greater variability and leads to an underestimation of the braking index in comparison with this new method of analysis.In Part III we tested the effectiveness of a training program by electrostimulation of the ankle plantar and dorsiflexors on the parameters related to the fall or its severity. This training increased the strenght, and probably the contraction speed of the ankle muscles. Although the rehabilitation of other muscles seems necessary to improve gait,the training program has rehabilitated dynamic balance.

Orientador: José Luiz Rybarczyk Filho / Resumo: O cavalo (Equus caballus) sofreu mudanças evolutivas do Eohypus com adaptações na locomoção para andamentos em diferentes velocidades. Em semelhança a outros ungulados a porção distal dos equinos é protegido pelo casco. O casco é estrutura córnea complexa que tem relação direta à saúde destes animais, é a parte protetora estrutural e funcional do sistema locomotor do equino, e tem ação direta sobre o retorno sanguíneo dos membros ao coração. Ao apoiar o casco sobre o solo, o animal pressiona as estruturas podais que promovem a expansão medial e lateral do casco. Considerando tais alterações no formato do casco nos momentos de apoio e elevação durante a locomoção, apresenta-se um sistema físico de precisão que analisa objetivamente a deformação dos cascos durante a locomoção, estabelecendo-se uma avaliação física e matemática das mudanças do formato do casco à locomoção. Foi desenvolvida uma placa de circuito impresso para se encaixar na plataforma embarcada Arduino (shield), esse dispositivo faz o processamento dos sinais adquiridos pelos sensores fixados nos cascos, e os enviam a um computador com uma taxa de amostragem a 200 Hz. Um software escrito na linguagem de programação Python recebe os dados, exibe-os em tempo real e os armazenam em arquivos para análises. Para realizar o teste in vitro foi criado um protótipo de um casco em PVC. Os testes in vivo foram feitos em quatro animais, o quais foram conduzidos em dois tipos diferentes de solo (asfalto e grama). O resultado ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The horse (Equus caballus) underwent evolutionary changes of Eohypus with adaptati- ons in locomotion for different speeds. In similarity to other angulated distal equine is protected by the hoof. The hoof is a complex cornea structure that is directly related to the health of these animals, it is the structural and functional protective part of the equine locomotor system, and has direct action on the blood return of the limbs to the heart. By supporting the hoof on the ground, the animal presses the foot structures that promote the medial and lateral expansion of the hoof. Considering such changes in the shape of the hoof during moments of support and elevation during locomotion, a physical precision system is presented that objectively analyzes the deformation of the hooves during the locomotion, establishing a physical and mathematical evaluation of the changes of the shape of the hoof to locomotion. A printed circuit board was developed to fit the Arduino embedded platform (shield), this device processes the signals acquired by the sensors attached to the hooves and sends them to a computer with a sampling rate of 200 Hz. Software written in the Python programming language receives the data, displays it in real time, and stores it in files for analysis. For the in vitro test a prototype of a PVC hoof was created. In vivo tests were performed on four animals, which were conducted on two different types of soil (asphalt and grass). The result demonstrated and proved the op... (Complete abstract click electronic access below) / Mestre

This study describes the development and testing of a virtual reality locomotion system that uses the user’s arm swings as input. This system has also been integrated with audio and haptic feedback that reacts to the user’s velocity and the surface they’re currently walking on, in an attempt to provide an intuitive and immersive VR locomotion experience. To achieve this, an open source ArmSwinger implementation has been adapted, and custom haptic belts were crafted to display haptic feedback around the user’s feet. Tests with three participants have shown that the system is able to be operated even by users unfamiliar with VR, and the addition of locomotion feedback mostly succeeds in improving the user experience, albeit some issues with synchronization were brought up. / Denna studie beskriver utvecklingen och testningen av ett virtuell verklighet lokomotivsystem som använder användarens armsvängningar som ingång. Detta system har också integrerats med ljud och haptisk feedback som reagerar på användarens hastighet och ytan de för närvarande går på, i ett försök att ge en intuitiv och uppslukande VV rörelseupplevelse. För att uppnå detta har en öppen källkod ArmSwinger implementering anpassats och anpassade haptiska bälten har utformats för att visa haptisk feedback runt användarens fötter. Test med tre deltagare har visat att systemet kan drivas även av användare som inte känner till VV, och tillägget av rörelseåterkoppling lyckas främst förbättra användarupplevelsen, även om vissa problem med synkronisering togs upp.

Through the Cenozoic, paleoclimate records show general trends of global cooling and increased aridity, and environments in North America shifted from predominantly forests to more open habitats. Paleobotanical records indicate grasses were present on the continent in the Eocene; however, paleosol and phytolith studies indicate that open habitats did not arise until the late Eocene or even later in the Oligocene. Studies of large mammalian herbivores have documented changes in ecomorphology and community structure through time, revealing that shifts in mammalian morphology occurred millions of years after the environmental changes thought to have triggered them. Smaller mammals, like rodents and lagomorphs, should more closely track climate and habitat changes due to their shorter generation times and smaller ranges, but these animals have received much less study. To examine changes in smaller mammals through time, we have assembled and analyzed an ecomorphological database of all North American rodent and lagomorph species. Analyses of these data found that rodent and lagomorph community structure changed dramatically through the Cenozoic, and shifts in diversity and ecology correspond closely with the timing of habitat changes. Cenozoic rodent and lagomorph species diversity is strongly biased by sampling of localities, but sampling-corrected diversity reveals diversity dynamics that, after an initial density-dependent diversification in the Eocene, track habitat changes and the appearance of new ecological adaptations. As habitats became more open and arid through time, rodent and lagomorph crown heights increased while burrowing, jumping, and cursorial adaptations became more prevalent. Through time, open-habitat specialists were added during periods of diversification, while closed-habitat taxa were disproportionately lost in subsequent diversity declines. While shifts among rodents and lagomorphs parallel changes in ungulate communities, they started millions of years earlier than in larger mammals. This is likely a consequence of the smaller mammal' greater sensitivity to environmental changes and more rapid evolution. These results highlight the importance of examining understudied members of vertebrate faunas for understanding the evolution of terrestrial communities through time.

One of the goals of neuroscience is to classify all of the neurons in the brain. Neuronal types can be defined using a combination of morphology, electrophysiology, and gene expression profiles. Gene expression profiles allow differentiation between cells that share similar characteristics. Leveraging the advantage of Berghia stephanieae (Gastropoda; Nudibranchia), which has around 28,000 neurons, I constructed high-throughput single-neuron transcriptomes for its whole brain. I produced a single-cell dissociation protocol and a custom data analysis pipeline for data of this nature. Around 129,000 cells were collected from 18 rhinophore ganglia and 20 circumesophageal ring ganglia (brain), consisting of the cerebropleural, pedal, and buccal ganglia. Messenger RNA libraries were constructed using the 10X Genomics’ Chromium platform. After library preparation, around 1,000 cells were recovered and sequenced. The HTStream package was utilized to trim off unwanted sequences from the raw reads and remove PCR duplicates and other contamination, then the salmon alevin package was employed to construct gene-by-cell matrices containing all the transcripts for each gene in each cell. The Seurat pipeline was used to extract this expression data from the matrices, normalize it, and perform dimensionality reduction. The cells were clustered based on similarities in their gene expression profiles. The cells formed eight clusters on a UMAP graph, each having distinct marker genes. Additionally, one cluster was composed of almost exclusively cells from the rhinophore ganglia, accounting for 30% of all rhinophore ganglion cells in the sample. Cells from the rhinophore ganglia are as heteregenous as cells from the rest of the brain, with cells forming six clusters. Cell populations that express the same neurotransmitter were identified for a wide range of both small-molecule neurotransmitters and neuropeptides. In a separate project, the locomotion of Berghia was recorded over 9 days with 2 lighting regimes: LD first and DD first. The results suggest that locomotion of Berghia is governed by circadian clock and that Berghia is nocturnal. Hunger state likely plays a role in modulating this circadian rhythm.

京都大学 / 0048 / 新制・課程博士 / 博士(生命科学) / 甲第18483号 / 生博第312号 / 新制||生||41(附属図書館) / 31361 / 京都大学大学院生命科学研究科統合生命科学専攻 / (主査)教授 上村 匡, 教授 垣塚 彰, 教授 藤田 尚志 / 学位規則第4条第1項該当 / Doctor of Philosophy in Life Sciences / Kyoto University / DFAM

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